1. Technical Field of the Invention
This invention is related generally to video processing devices, and more particularly to the preparation of video information to be displayed on a video player.
2. Description of Related Art
Movies and other video content are often captured using 35 mm film with a 16:9 aspect ratio. When a movie enters the primary movie market, the 35 mm film is reproduced and distributed to various movie theatres for sale of the movie to movie viewers. For example, movie theatres typically project the movie on a “big-screen” to an audience of paying viewers by sending high lumen light through the 35 mm film. Once a movie has left the “big-screen,” the movie often enters a secondary market, in which distribution is accomplished by the sale of video discs or tapes (e.g., VHS tapes, DVD's, high-definition (HD)-DVD's, Blue-ray DVD's, and other recording mediums) containing the movie to individual viewers. Other options for secondary market distribution of the movie include download via the Internet and broadcasting by television network providers.
For distribution via the secondary market, the 35 mm film content is translated film frame by film frame into raw digital video. For HD resolution requiring at least 1920×1080 pixels per film frame, such raw digital video would require about 25 GB of storage for a two-hour movie. To avoid such storage requirements, encoders are typically applied to encode and compress the raw digital video, significantly reducing the storage requirements. Examples of encoding standards include, but are not limited to, Motion Pictures Expert Group (MPEG)-1, MPEG-2, MPEG-2-enhanced for HD, MPEG-4 AVC, H.261, H.263 and Society of Motion Picture and Television Engineers (SMPTE) VC-1.
To accommodate the demand for displaying movies on telephones, personal digital assistants (PDAs) and other handheld devices, compressed digital video data is typically downloaded via the Internet or otherwise uploaded or stored on the handheld device, and the handheld device decompresses and decodes the video data for display to a user on a video display associated with the handheld device. However, the size of such handheld devices typically restricts the size of the video display (screen) on the handheld device. For example, small screens on handheld devices are often sized just over two (2) inches diagonal. By comparison, televisions often have screens with a diagonal measurement of thirty to sixty inches or more. This difference in screen size has a profound affect on the viewer's perceived image quality.
For example, typical, conventional PDA's and high-end telephones have width to height screen ratios of the human eye. On a small screen, the human eye often fails to perceive small details, such as text, facial features, and distant objects. For example, in the movie theatre, a viewer of a panoramic scene that contains a distant actor and a roadway sign might easily be able to identify facial expressions and read the sign's text. On an HD television screen, such perception might also be possible. However, when translated to a small screen of a handheld device, perceiving the facial expressions and text often proves impossible due to limitations of the human eye.
Screen resolution is limited if not by technology then by the human eye no matter what the size screen. On a small screen however, such limitations have the greatest impact. For example, typical, conventional PDA's and high-end telephones have width to height screen ratios of 4:3 and are often capable of displaying QVGA video at a resolution of 320×240 pixels. By contrast, HD televisions typically have screen ratios of 16:9 and are capable of displaying resolutions up to 1920×1080 pixels. In the process of converting HD video to fit the far lesser number of pixels of the smaller screen, pixel data is combined and details are effectively lost. An attempt to increase the number of pixels on the smaller screen to that of an HD television might avoid the conversion process, but, as mentioned previously, the human eye will impose its own limitations and details will still be lost.
Video transcoding and editing systems are typically used to convert video from one format and resolution to another for playback on a particular screen. For example, such systems might input DVD video and, after performing a conversion process, output video that will be played back on a QVGA screen. Interactive editing functionality might also be employed along with the conversion process to produce an edited and converted output video. To support a variety of different screen sizes, resolutions and encoding standards, multiple output video streams or files must be generated.
Video is usually captured in the “big-screen” format, which server well for theatre viewing. Because this video is later transcoded, the “big-screen” format video may not adequately support conversion to smaller screen sizes. In such case, no conversion process will produce suitable video for display on small screens. Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of ordinary skill in the art through comparison of such systems with various aspects of the present invention.